JP3094985B2 - Optical head device and optical disk device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The invention described in the claims of the present application makes a light beam incident on a disk through an objective lens, and relates to a light beam incident on the disk. Ru <br/> relates to a focus control and tracking control lines cormorants optical <br/> Science head device and an optical disc apparatus using the same. 2. Description of the Related Art In an optical disk player for reproducing information from a disk-shaped recording medium, an optical head device constituting an optical system for reading information from a recording track formed on the disk-shaped recording medium is provided. Be provided. In such an optical head device, for example, as shown in a simplified form in FIG. 5, the entire device including a semiconductor laser 61 and a photodetector 70 is integrally formed as one unit, and a disk D To be able to move along the radial direction. Then, the laser light emitted from the semiconductor laser 61 is diffracted by the grating 62 into three laser light beams (in FIG. 5, these three laser light beams are indicated by one line for simplicity). The direction of the optical axis is changed by the polarizing beam splitter 63 and the light enters the collimator lens 64. Then, the laser light beam converted into a parallel light beam by the collimator lens 64 is made incident on the disk D through the objective lens 66, and is reflected by being modulated on a recording track formed on the disk D. [0004] The reflected laser light beam from the disk D is
The light passes back through the objective lens 66 and the collimator lens 64 in order, and passes through the polarizing beam splitter 63 without changing its optical axis direction.
The light is guided to the photodetector 70 through 8. Then, a detection output obtained from the photodetector 70 is supplied to a signal processing unit (not shown) to form a reproduction information signal, a focus control signal, and a tracking control signal. The focus control signal and the tracking control signal are respectively provided by a focus control driving unit 71 disposed in relation to the objective lens 66.
And is supplied to a tracking control drive section 72, thereby moving the objective lens 66 along the optical axis of the disc D.
A drive operation for focus control is performed to move the objective lens 66 closer to or away from the disk D, and the objective lens 66 is moved in a radial direction of the disk D, which is a direction orthogonal to the optical axis, for tracking control. The driving operation is performed. In the optical head device, a mechanism (hereinafter, referred to as a two-axis driving unit) for performing such a driving operation for focus control and a driving operation for tracking control has, for example, a structure as shown in FIG. It is assumed to have. The biaxial drive unit shown in FIG. 6 has a base 80 made of a metal material fixed on a slide base movable in the radial direction of the disk.
A shaft 82 is erected substantially at the center of the base 80. The shaft 82 is loosely inserted into a center hole formed at the center of a lens holding member 84 that holds the objective lens 66. Lens holding member 84 rotatable about 82
, A cylindrical bobbin 86 is attached. A focus control coil 88 is wound on the outer peripheral surface of the bobbin 86, and a tracking control coil 90 is further disposed on the focus control coil 88 via an insulating film. The winding axis direction of the tracking control coil 90 is orthogonal to the winding axis direction of the focus control coil 88. A pair of arc-shaped magnetic yokes 92 are erected on the upper surface of the base 80 on which the shaft 82 is erected.
Further, a focus control coil 88 is attached to each magnetic yoke 92.
A pair of magnetic yokes 94 are provided at positions facing each other with the. Each magnetic yoke 94 is fixed to the upper surface of the base 80 via a magnet not shown in FIG.
Further, a pair of magnetic yokes 92 are provided on the upper surface of the base 80.
Lens holding member 84 in a direction orthogonal to
A pair of magnets 96 facing each other across the
It is arranged and supported by. The magnetic yokes 92 and 94, and the magnet and the magnet 96 disposed between the magnetic yoke 94 and the base 80 form a magnetic field forming unit for the focus control coil 88 and the tracking control coil 90. The focus control coil 88 wound around the bobbin 86 is positioned in a magnetic gap formed between the magnetic head and the magnetic yoke 94 to form a focus control drive unit. A tracking control drive section is formed at a position facing each of the pair of magnets 96. When a driving operation for focus control is performed by the two-axis drive unit having such a configuration, the focus control signal is transmitted to the focus control coil 8.
8 is supplied. Thereby, the focus control coil 8
8 receives a force according to the polarity and level of the focus control signal from the magnetic field formed by the magnetic gap between the magnetic yoke 92 and the magnetic yoke 94, and the bobbin 86 moves along the axis 82 erected on the base 80. The objective lens 66 is moved upward or downward to move in a direction along the optical axis. On the other hand, when a driving operation for tracking control is performed, a tracking control signal is supplied to the tracking control coil 90. Accordingly, the pair of tracking control coils 90 receive a force corresponding to the polarity and level of the tracking control signal from the magnetic field formed by the magnets 96 facing each other, and the bobbin 86 moves the shaft 82 erected on the base 80. The object lens 66 is rotated clockwise or counterclockwise as the center, and moves the objective lens 66 in a direction perpendicular to its optical axis. In the optical head device as described above, the base 80 and a pair of magnetic yokes 92 and a pair of magnet support portions 98 forming a magnetic field forming portion are usually provided.
The base member 100 is formed integrally with, for example, a plurality of standing portions (the magnetic yoke 92 and the magnet support portion 98) projecting from a flat plate portion (the base 80) as shown in FIG. Is used. And such a base 80
Member 1 having an integral structure of a magnetic yoke 92 and the like
00 is formed by casting using a mold formed by the lost wax method, for example. As described above, the base 80 and the magnetic yoke 92
When the base member 100 is formed by casting, the manufacturing cost increases, and not only the design restrictions on the shape and the like of the magnetic yoke 92 in the base member 100 become large, but also In addition, there is a problem that it is difficult to improve the accuracy of the base member 100. In view of the above, the invention described in the claims of the present application provides a magnetic yoke constituting a magnetic field forming unit for a focus control coil and a tracking control coil in a two-axis drive unit, and supports the magnetic yoke. base that is obtained under a reduced manufacturing cost, moreover, is intended to design flexibility is improved accuracy while being large, optical science head device and it
Provided is an optical disk device used . An optical head device according to the invention described in claim 1 of the present application is a lens holding member for holding an objective lens, and is attached to the lens holding member. and coil, with the magnetic plate member is made first and second bent upright piece being machined bent is provided integrally, the magnet is arranged on the first bent upright piece, first A magnetic yoke member having a magnetic field forming portion with the second bent upstanding pieces facing each other, and a lens holding member in a state in which a coil is disposed in the magnetic field forming portion, along the optical axis of the objective lens A support member that is displaceably supported in a first direction and a second direction orthogonal to the first direction; a light source that emits laser light; a laser light that is emitted from the light source; and a reflected laser light that is reflected from a recording medium. Element for separating light and recording medium And a slide base to which a magnetic yoke member and a support member are attached. Also, in the optical disk device according to the invention described in claim 2 of the present application, the lens holding member holding the objective lens, the coil attached to the lens holding member, and the magnetic plate member are bent. processed by first and second folding standing piece is made integrally provided, together with the magnets arranged on the first bent upright piece, the first and second folding standing piece A magnetic yoke member which is opposed to form a magnetic field forming portion, and a lens holding member in a state where a coil is arranged in the magnetic field forming portion, and a first direction along the optical axis of the objective lens and the first direction thereof A supporting member that is displaceably supported in a second direction perpendicular to the optical axis, a light source that emits laser light, an optical element that separates laser light emitted from the light source from reflected laser light from a recording medium, and a recording medium Detection that the reflected laser light from Together with the optical unit is provided configured with the vessel,
A slide base to which the magnetic yoke member and the support member are attached, and a guide portion for guiding the movement of the slide base are provided. In the optical head device according to the first aspect of the present invention configured as described above, the magnetic plate member is bent and the first and second bent portions are formed. standing piece is magnetic yoke members formed integrally provided, the slide base which is formed separately from the magnetic yoke member, is fixedly adjusted position, magnet arrangement to the first bent standing piece Then, a magnetic field forming portion is formed by the first bent upright piece and the second bent upright piece, and is attached to a lens holding member holding the objective lens in a magnetic field formed by the magnetic field forming portion. The positioned coil is positioned. Then, under such a state, the supporting member that supports the lens holding member so as to be able to move is a light source that emits laser light guided to the objective lens, and a laser light emitted from the light source and a light source that passes through the objective lens. An optical element including an optical element that separates a reflected laser beam from the recording medium obtained by reflecting the laser beam on the recording medium, a photodetector that guides the reflected laser beam from the recording medium, and a magnetic yoke Attached to the slide base with the members,
A predetermined focus control signal and tracking control signal based on the detection output sent from the photodetector are supplied to the coil, so that the objective lens held by the lens holding member moves in a direction along the optical axis and orthogonally to the direction. Moved in the direction. [0013] Thus, the magnetic yoke member, a set of folding standing piece for the magnetic plate member constituting been processed bent magnetic field forming portion is formed is provided, separately from the magnetic yoke member formed in Rutotomoni, a light source, a particular optical element, an optical test
The slide base and the magnetic yoke member are integrated with each other by being attached to the slide base provided with the optical unit including the ejector and the like so that the position can be adjusted. The production cost is reduced as compared with the case where the molding is performed by casting, and
The restriction on the design of the magnetic yoke member and the slide base is eased, and the accuracy is improved. The optical head device according to the first aspect of the present invention, which has such advantages, is provided, and the optical head device according to the first aspect of the present invention includes a guide portion. In the optical disk device according to the second aspect of the present invention, the slide base is moved with high accuracy by the guide portion for the slide base constituting the optical head device. [0014] Figures 1 and 2 DETAILED DESCRIPTION OF THE INVENTION, wherein in an example and claims of the engagement Ru optical science head apparatus to the invention described in claim 1 in the claims of the present application
Is an exploded perspective view and an external view showing a main part of an example of an optical disk apparatus according to the invention described in claim 2, 3, the invention described in claim 1 in the claims of the present application <br /> An example and claims of the engagement Ru optical science head device
An optical disc device according to the invention described in claim 2
The main part of an example of the device is shown in a simplified manner together with the disk . In the example shown in FIG. 3, a laser beam emitted from a semiconductor laser 1 is diffracted by a grating 2 into three laser beams (in FIG. 3,
For simplicity, these three laser light beams are shown as one line. ), Reflected by the plate-shaped beam splitter 3 and incident on the collimator lens 4. Then, the laser beam converted into a parallel light beam by the collimator lens 4 is
The light is made incident on the disk D through the objective lens 6 and is reflected by being modulated on the recording track formed on the disk D. A focus control drive unit 11 and a tracking control drive unit 12 are arranged around the objective lens 6. The reflected laser light beam from the disk D is
After sequentially passing through the objective lens 6 and the collimator lens 4 and returning and passing through the plate-shaped beam splitter 3, the correction glass plate 7 corrects the coma aberration received when passing through the plate-shaped beam splitter 3, and receives the light-receiving lens ( concave lens)
The light is guided to the photodetector 10 through 8. Then, a detection output obtained from the photodetector 10 is supplied to a signal processing unit (not shown) to form a reproduction information signal, a focus control signal, and a tracking control signal. The focus control signal and the tracking control signal are supplied to a focus control drive unit 11 and a tracking control drive unit 12, respectively, which are arranged in relation to the objective lens 6, thereby moving the objective lens 6 along its optical axis. In the direction to move closer to or away from the disk D,
Drive operation for focus control is performed,
A driving operation for tracking control is performed to move the objective lens 6 in the radial direction of the disk D, which is a direction orthogonal to the optical axis. In this example, the semiconductor laser 1, grating 2, plate beam splitter 3, collimator lens 4, correction glass plate 7, light receiving lens 8, and photodetector 10 are mechanically integrated into one block. And constitutes the light beam generation / detection unit 14. The objective lens 6, the focus control drive unit 1
1 and the tracking control drive unit 12 are mechanically combined into one other block to form a two-axis drive unit 20.
It is assumed to constitute. As shown in FIG. 4, the light beam generation / detection unit 14 and the biaxial drive unit 20 are each a block housed in a case, and the guide shaft 1 extends in the radial direction of the disk D.
6 is attached to the slide base 18 which moves while being guided. The slide base 18 has a
To the magnetic yoke member 24 which is mounted as
A round hole into which the guide shaft 16 is inserted on the side and the other side
Is provided on the bearing portion 19 provided with
Thus, the formed engaging portions are provided integrally.
It has been. Engagement formed by a pair of protrusions 21
The joint has a substantially U-shaped cross section, and
Engage with the guide plate member 23 extending in the radial direction
To form a guided portion together with the bearing portion 19.
You. The guide shaft 16 and the guide plate member 23 are a pair.
The engaging portion and the bearing portion 16 formed by the projecting portion 21
By guiding the configured guided portion, the slide base 18
For moving the disc along the radial direction of the disc D
Unit. In this way, the scope of the claims of the present application is as follows .
An example of the optical head device according to claim 1 and a book
The optical device according to claim 2 in the claims of the application.
Of the light beam generation / detection unit 14 and the two-axis drive unit 20 that constitute an example of the disk device , the two-axis drive unit 20 is configured as shown in FIGS. 1 and 2, for example. The example of the biaxial drive unit 20 shown in FIG. 1 has a base 22 which is attached to the upper surface side of the slide base 18 shown in FIG. I have. This base 22
A through hole 22a is formed at the center thereof, and the through hole 22a is located right above the through hole 18a provided in the slide base 18. A magnetic yoke member 24 formed by processing a magnetic plate member into a sheet metal is fixed to the upper surface side of the base 22 with screws 26. In the magnetic yoke member 24, two sets of opposed bent upright pieces 28a and 28b and a supporting bent upright piece 35 are provided on a magnetic plate member by bending. The magnet 30 is fixed to each bent upright piece 28a. Then, the focus control driving unit 1 together with a focus control coil and a tracking control coil to be described later are formed by the bent upright pieces 28a and 28b and the magnet 30.
1 and a magnetic field forming unit constituting the tracking control drive unit 12 are formed. At a predetermined position of the magnetic yoke member 24, an elongated hole 32 into which the screw 26 is inserted is formed. When the magnetic yoke member 24 is fixed to the base 22 by the screw 26, a fine hole with respect to the base 22 is formed. The position can be adjusted. Further, a pair of through holes 34 are formed in the vicinity of the elongated holes 32 in the magnetic yoke member 24, and a pair of pins which are inserted into the through holes 34 and protrude to the upper surface side of the magnetic yoke member 24. The movable member 38
Is attached. The movable member 38 has a pair of through holes 40a into which the pins 36 are inserted, and a fixed end 40 whose lower surface is in contact with the flange of the pin 36, and an upper edge of the fixed end 40. A pair of arm members 42 connected to the lower end edge via a hinge portion 42a and swingable in a direction perpendicular to the guide shaft 16 shown in FIG. The upper end edge and the lower end edge are connected to the other ends of the arm members 42 via hinge portions 42b, respectively, and the plate-like member 4 which can be swung by the hinge portions 46a.
6 are provided. Then, the plate-like member 46
Is fitted in a notch 49 formed in a bobbin member 48 that holds the objective lens 6. The bobbin member 48 includes a lens fixing portion 50 to which the objective lens 6 is attached, and an arm member 42 of the movable member 38 in a state where the plate-like member 46 of the movable member 38 is fitted into the notch 49. It has a pair of side plate members 52 that form a gap to be loosely inserted. And
The lens fixing portion 50 and the pair of side plate members 52 are formed with two sets of opposed protrusions 50a and 52a,
Between each pair of the projections 50a and 52a, a focus control coil 54 wound in a cylindrical shape, and the focus control coil 54 is wound in the direction of the winding axis of the focus control coil 54. Tracking control coil 5 which is insulated and adhered so as to be orthogonal to
5 are arranged. That is, in this example, the movable member 38
The bobbin member 48 fixed to the movable member 38 constitutes a lens holding member that holds the objective lens 6 in a swingable manner. Then, the bobbin member 48 is
8, the movable member 38 is connected to the pair of pins 36.
Is attached to the magnetic yoke member 24 via
A pair of focus control coils 54 are fitted to the bent upright pieces 28b provided on the magnetic yoke member 24 together with the tracking control coils 55, respectively. On the upper end surfaces of the pair of side plate members 52 of the bobbin member 48, a focus control coil 54 and a tracking control coil 55 are connected to a focus control signal supply unit and a tracking control signal supply unit, respectively. One end of a flexible connection substrate 58 formed by printing a lead wire on a polyimide resin thin film is fixed. The other end of the flexible connection board 58 is connected to the bobbin member 4 through a cutout 49 formed in the bobbin member 48.
The magnetic yoke member 8 is guided to the lower surface side and is fixed to a supporting bent piece 35 provided on the magnetic yoke member 24. The magnetic yoke member 24 to which the magnet 30 is fixed, the movable member 38, the bobbin member 48, the focus control coil 54, the tracking control coil 55, and the flexible connection board 58 are in an assembled state. As shown in FIG. 2, the magnetic yoke member 24 has a mutual arrangement relationship, and is composed of bent upright pieces 28a and 28b provided on the magnetic yoke member 24 and a magnet 30 fixed to the bent upright piece 28a. The focus control coil 54 and the tracking control coil 55 are located in a magnetic gap formed between the bent upright piece 28b and the magnet 30 in the magnetic field forming section. And, as mentioned above,
A magnetic yoke member 24 is attached to a base 22 attached to the slide base 18 so as to be position-adjustable by screws 26. Further, various members arranged on the base 22 are all transparent to positions corresponding to the objective lens 6. Hole 56a
Is covered by the case 56 in which The two-axis drive unit 2 configured as described above
When a driving operation for focus control by 0 is performed, a focus control signal is supplied from the focus control signal supply unit to the focus control coil 54 through the flexible connection board 58, whereby each of the pair of focus control coils 54 In the magnetic field formed by the magnetic field forming portion constituted by the bent upright pieces 28a and 28b provided on the magnetic yoke member 24 and the magnet 30 fixed to the bent upright piece 28a, It receives an electromagnetic force according to the polarity and level of the focus control signal that is to be moved. Therefore, the bobbin member 48 to which the focus control coil 54 is fixed is moved in the X-axis direction together with the arm member 42 of the movable member 38. As a result, the objective lens 6 fixed to the bobbin member 48 It is moved in the axial direction according to the focus control signal. When a driving operation for tracking control is performed, a tracking control signal is supplied from the tracking control signal supply unit to the tracking control coil 55 through the flexible connection substrate 58, whereby a pair of tracking control coils 55 is provided. Are bent upright pieces 28a and 28b provided on the magnetic yoke member 24.
And a magnetic field formed by a magnetic field forming part constituted by the magnet 30 fixed to the bent upright piece 28a,
One of which is brought close to the magnet 30 facing it,
On the other hand, it receives an electromagnetic force according to the polarity and level of the tracking control signal, which is made to be separated from the magnet 30 facing it. Accordingly, the bobbin member 48 to which the tracking control coil 55 is fixed via the focus control coil 54 is rotated around the hinge 46a of the movable member 38 as a fulcrum, and as a result, the object fixed to the bobbin member 48 is rotated. The lens 6 is moved in a direction orthogonal to the optical axis direction, that is, in a direction along the guide shaft 16 shown in FIG. 4, according to the tracking control signal. As is clear from the above description, the optical head device according to the invention described in claim 1 of the present application and the optical head device described in claim 2 of the present application are described. According to each of the optical disk devices according to the present invention, a magnetic yoke member constituting a magnetic field forming portion for applying an electromagnetic force according to a focus control signal and a tracking control signal supplied to a coil in a biaxial drive unit to the coil but the magnetic plate body is assumed to be obtained by sheet metal processing, and the magnetic yoke member is formed separately from that Rutotomoni, a light source, a particular optical element
An optical unit including a detector and a photodetector is provided.
Since the slide base is mounted on the slide base so as to be adjustable in position, for example, the manufacturing cost is greatly increased as compared with a case where the slide base and the magnetic yoke member are integrated and molded by casting. Can be reduced. Further, the degree of freedom in designing the shapes or dimensions of the magnetic yoke member and the slide base is increased, and the accuracy of the magnetic yoke member and the slide base can be improved.

An example of engaging Ru optical science head apparatus to the invention described in claim 1 in the range BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] following claims and the present application in Japanese
According to the invention described in claim 2 in the scope of the claims
FIG. 3 is an exploded perspective view for explaining a configuration of a main part in an example of the optical disk device . 2 is a perspective view of a main part in the example Ru shown in Figure 1. [3] One example and application of Japanese in the present engagement Ru optical science head apparatus to the invention described in claim 1 in the appended claims
According to the invention described in claim 2 in the scope of the claims
FIG. 3 is a simplified configuration diagram illustrating an example of an optical disk device . 4 is an external perspective view of the example shown in FIG. FIG. 5 is a simplified configuration diagram showing an example of an optical head device of a conventional disk player. 6 is a perspective view of a main part in the conventional example shown in FIG. FIG. 7 is a perspective view of a main part in the conventional example shown in FIG. [Brief description of reference numerals] 6 Objective lens 11 Drive unit for focus control
12 Tracking control drive unit 14 Light beam generation / detection unit 19 Bearing unit 20 Biaxial drive unit 21 Projection unit 22 Base
23 guide plate member 24 magnetic yoke member 28a, 28b bent upstanding piece 30 magnet
38 movable member 48 bobbin member 54
Focus control coil 55 Tracking control coil

Claims (1)

(57) [Claims] A lens holding member for holding the objective lens, a coil attached to the lens holding member, and a magnetic plate member being bent to be integrally provided with first and second bent upright pieces; with magnets is arranged on the first bent upright piece, a magnetic yoke member said first and second folding standing piece constitute a magnetic field forming portion is opposition, the lens holding member above A support member configured to displace in a first direction along the optical axis of the objective lens and a second direction orthogonal to the first direction, with the coil being arranged in the magnetic field forming unit; A light source that emits laser light, an optical element that separates laser light emitted from the light source from reflected laser light from a recording medium, and a photodetector that guides reflected laser light from the recording medium Optical unit is provided An optical head device comprising: a slide base to which the magnetic yoke member and the support member are attached. 2. A lens holding member for holding the objective lens, a coil attached to the lens holding member, and a magnetic plate member being bent to be integrally provided with first and second bent upright pieces; with magnets is arranged on the first bent upright piece, a magnetic yoke member said first and second folding standing piece constitute a magnetic field forming portion is opposition, the lens holding member above A support member configured to displace in a first direction along the optical axis of the objective lens and a second direction orthogonal to the first direction, with the coil being arranged in the magnetic field forming unit; A light source that emits laser light, an optical element that separates laser light emitted from the light source from reflected laser light from a recording medium, and a photodetector that guides reflected laser light from the recording medium Optical unit is provided An optical disk device comprising: a slide base to which the magnetic yoke member and the support member are attached; and a guide unit for guiding the movement of the slide base.